﻿using System;
using System.Windows.Input;
using System.Diagnostics;

namespace JPR.TunelProxy.RequestGenerator.ViewModel
{
	/// <summary>
	/// Helper class to relay a command to a predefined Action.
	/// </summary>
	public class RelayCommand : ICommand
	{
		private readonly Action<object> _execute;
		private readonly Predicate<object> _canExecute;

		public RelayCommand(Action<object> execute)
			: this(execute, null)
		{ }

		public RelayCommand(Action<object> execute, Predicate<object> canExecute)
		{
			if (execute == null)
				throw new ArgumentNullException("execute");

			_execute = execute;
			_canExecute = canExecute;
		}

		#region ICommand Members

		[DebuggerStepThrough]
		public bool CanExecute(object parameter)
		{
			return _canExecute == null ? true : _canExecute(parameter);
		}

		public event EventHandler CanExecuteChanged
		{
			add { CommandManager.RequerySuggested += value; }
			remove { CommandManager.RequerySuggested -= value; }
		}

		public void Execute(object parameter)
		{
			_execute(parameter);
		}

		#endregion
	}
}
